For a monoatomic gas, the value of the ratio of ${\mathrm{C}}_{\mathrm{p}.\mathrm{m}}$ and ${\mathrm{C}}_{\mathrm{v}.\mathrm{m}}$ is:

One mole of an ideal monoatomic gas is made to go through the cycle as shown in figure. Then the change in the internal energy in expanding the gas from $a$ to $c$ along the path $abc$ is

The $\mathrm{P}-\mathrm{T}$ graph as given below was observed for a process on an ideal gas, which of the following statement is true.

The difference between heats of reaction at constant pressure and constant volume for the reaction

$2{\mathrm{C}}_6{\mathrm{H}}_6\left(\mathrm{l}\right)+15{\mathrm{O}}_2\left(\mathrm{g}\right)\to 12{\mathrm{CO}}_2\left(\mathrm{g}\right)+6{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$ at $25°$ in $\mathrm{kJ} {\mathrm{mol}}^{-1}$ is:-.